The overall objective of this Phase II program is to provide enabling technology to carry out experiments in gene regulation without having to obtain microbiological expertise or use radioactive materials. The research objectives are to (1) develop novel, non-microbiological methods for obtaining hapten-conjugated cRNA probes, which were demonstrated in Phase I to be far superior to hapten-conjugated synthetic oligodeoxyribonucleotide probes, and (2) compare the utility of cRNA probes prepared in this manner to microbiologically-obtained cRNA probes. Probe performance will be determined by solution hybridization, Northern hybridization, and in situ hybridization of striatal and cortical preproenkephalin mRNA. The quantitative potential of these probes in all three hybridization formats will also be explored in studies of preproenkephalin mRNA regulation during chronic exposure of rats to the antipsychotic drug haloperidol. While these studies will be carried out with brain preproenkephalin mRNA as the focus, the technology should have broad applicability to the study of diverse mRNAs in brain and other tissues. This new technology will form the basis for the development of novel research and diagnostic products, which should enhance research efforts in basic and clinical neurosciences.